Piston-ring



H. A. W AINWRIGHTK PISTON RING.

APPLICATION FILED AUG I3, I919.

1 0 1,93 Patented Dec. 27, 1921.

HARRY ARCHIBALD WAINWRIGHT, OF

CONNERSVILLE, INDIANA, ASSIGNOR T0 WAINWRIGHT ENGINEERING CORPORATION, OF CONNERSVILLE. INDIANA, A

CORPORATION OF INDIANA.

PISTON-RING.

Specification of Letters Patent. I Patented Dec, 27,1921,

Application filed August 13, 1919, Serial No. 317,216.

new and useful Piston-Ring, of which the following is a specification.

It is the object of my invention to produce a piston ring which reduces leakage to a minimum.

The accompanying drawing illustrates my invention: In such drawing, Figure 1 is a fragmentary plan of a piston ring embodying my invention; Fig. 2 is an edge view of such piston. ring on a somewhat larger scale; Fig. 3 is a fragmentary sectional view of a cylinder and pistonequipped with my improved piston ring, the piston-ring being in section on the line 3-3 of Fig. 2, and clearances being greatly exaggerated; and Fig. 4 is a section on the line 4-4 of Fig. 2;

The piston ring 10 is split in, the usual manner, as shown having the usual diagonal split 11; a1nd it is mounted in the usual pis ton-ring groove 12 in a piston 13 so that its outer face bears against the inner surface -of a cylinder 14. All this is as usual.

The outer peripheral surface of the piston ring, abutting against the inside wall of the cylinder, is provided with a seriesof circumferentially short, overlapping, oblique grooves 15, which are superficial grooves only and do not extend through the ring. These grooves 15 overlap each other so that preferably there are always at least two such grooves, and in many places three such grooves, onany line drawn across the peripheral face of the piston ring parallel to the axis. i r

In operation, assuming the piston and cyl-. inder to be those of an internal combustion .engine, when the explosionoccurs the explo, sion' ressure tends to force the gases past the piston between it and the cylinder wall. This is largely prevented by the tight fit of the piston ring against the cylinder wall, in-

the usual manner. However, as this fit "is never perfect, some of the gases force'thelr way betweentheperipheral face of the iston ring and the adjacent part of the ey inder wall and tend to crowd past the. open grooves 15 in the outer face of the PiSton ring. lVhen these gases reach such a groove,-

they circulate therein in small eddy currents, which whirl at high velocity and produce a substantially perfect seal between thepiston ring and the cylinder wall. This is probably due to the centrifugal action of the rapidly whirling eddy currents. Should there be. any slight leakage past the first groove 15, such leakage is stopped at the latter" grooves which the gases encounter in their attempted escape past the piston ring, as there are always two and sometimes three such grooves in any path of escape. Thus this makes a very effective preventive "of leakage.

To obtain the best action, the grooves 15 should be relatively short circumferentially, as if. they are too-long the leakage increases, probably due to the fact that instead of setting up eddy currents at any point to prevent}- leakage the gases which enter the groo es 15 tend to travel circumferentially arou d the piston ring by way of such groo es. Therefore, I make the grooves 15 com aratively short, circumferentially as show in order to obtain the best results.

In addition to the oblique overlapping grooves 15, I preferably provide interconnecting notches 16 which connect adjacent grooves 15, preferably at their middle points.

These notches'ltl may together constitute a continuous circumferential groove around the ringsave at the split 11. The interconnecting notches 16 are preferably of very much smaller cross-section than are the slots 15. By this construction, these notches 16 .do not interfere with the whirling eddy currents in the grooves15, and so do not interfere with the sealing action of such eddy currents. Indeed, they assist in such sealing action, for although not bigenough in cross-section to interfere with the production of the whirling ed y currents they allow the dissipation aroun the ring of any excess pressure which for any reason may tend'to develop at any point between the face of the piston ring and the cylinderwall and which '1 100 'save for such dissipation mi ht tend to force the piston ring away from't e cylinder wall at that point.

I claim as my. invention:

1. A piston ring having on its peripheral face a circumferential series of oblique overlapping grooves, said grooves being so arranged that at any point around the piston there are always two grooves along a line parallel to the axis.

2. A piston ringhaving on its peripheral face a circumferential series of circumferentially short oblique overlapping grooves. 3. A piston ring having on its peripheral face a circumferential series of oblique overlapping grooves; V V I I A. piston ring having on its peripheral face a circumferential series of oblique overlapping grooves, the peripheral face of said piston ring also having notches which interconnect adjacent oblique grooves substantially at their middle points.

5. A piston ring having on its peripheral face a circumferential series ofoblique overlapping grooves, the peripheral face of said piston ringalso having notches which interconnect ad acent obllque grooves.

(3. A piston ring having on its peripheral face a circumferential series of oblique overlapplng grooves, the peripheral face of said piston ring also having notches which inter-.

HARRY ARCHIBALD WAlNWRlGHT. 

